Strap part number for 5020

Hi wondering if someone can advise the part number for a 22mm small black calfskin strap that comes on the ceramic BP 5020?

my croco strap on my 5009 is either too loose or too tight given the hole placement and the slight stretch in the hole over time, I want to test over a period that the small strap will work for my wrist, given the one on the 5020 is about half the price thought this was a logical first move.

thanks

any ideas?

thanks Tony